The compound EMD281014 is known from European Patent EP 1 198 453 B1 and has the following structure:

EMD281014 exhibits, inter alia, effects on the central nervous system while being well tolerated and at the same time has valuable pharmacological properties. Thus, the substance has strong affinity to 5-HT2A receptors, while having 5-HT2A receptor-antagonistic properties.
A number of medical uses of EMD281014, for example the treatment of schizophrenia and sleeping disorders, are described in EP 1 198 453 B1. Further medical uses are the subject-matter of WO 03/45392 and WO 04/32932.
Processes for the preparation of EMD0281014 are disclosed in European Patents 1 198 453 B1 and 1 353 906 B1.
As the final process step in each case, the hydrochloride is precipitated from a solution of the free base by addition of an aqueous HCl solution and is separated off from the reaction mixture.
This known procedure always gives a crystal form A, which is characterised by the lattice spacing indicated in Table I, determined by X-ray powder diffraction.
Surprisingly, the inventors of the present patent application have found that a second crystal form B is formed on pressing of EMD281014 to give tablets under mechanical pressure and is present in significant amounts besides form A in the tablets produced. The amount of form B formed depends on the pressing pressure used.
It is extremely disadvantageous for a medicament tablet to comprise a plurality of crystal forms of an active ingredient alongside one another if these crystal forms have different bioavailabilities, for example if they dissolve at different rates under physiological conditions. Even slight variations in the production conditions would then cast doubt on the reproducibility of the bioavailability.
The object of the present invention was therefore to provide EMD281014 in a form which does not change its properties under the tabletting conditions and is therefore suitable for the production of tablets of defined and constant quality.